<?php

namespace App\Models\Products;

use App\Traits\BelongsToTenant;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;

/**
 * 단가 변경 이력 모델
 *
 * @property int $id
 * @property int $tenant_id
 * @property int $price_id
 * @property int $revision_number
 * @property \Carbon\Carbon $changed_at
 * @property int $changed_by
 * @property string|null $change_reason
 * @property array|null $before_snapshot
 * @property array $after_snapshot
 */
class PriceRevision extends Model
{
    use BelongsToTenant;

    public $timestamps = false;

    protected $fillable = [
        'tenant_id',
        'price_id',
        'revision_number',
        'changed_at',
        'changed_by',
        'change_reason',
        'before_snapshot',
        'after_snapshot',
    ];

    protected $casts = [
        'revision_number' => 'integer',
        'changed_at' => 'datetime',
        'before_snapshot' => 'array',
        'after_snapshot' => 'array',
    ];

    /**
     * 단가 관계
     */
    public function price(): BelongsTo
    {
        return $this->belongsTo(Price::class, 'price_id');
    }

    /**
     * 변경자 관계
     */
    public function changedByUser(): BelongsTo
    {
        return $this->belongsTo(\App\Models\Members\User::class, 'changed_by');
    }

    /**
     * 변경된 필드 목록 추출
     */
    public function getChangedFields(): array
    {
        if (! $this->before_snapshot) {
            return array_keys($this->after_snapshot ?? []);
        }

        $changed = [];
        foreach ($this->after_snapshot as $key => $newValue) {
            $oldValue = $this->before_snapshot[$key] ?? null;
            if ($oldValue !== $newValue) {
                $changed[] = $key;
            }
        }

        return $changed;
    }

    /**
     * 특정 필드의 이전/이후 값
     */
    public function getFieldChange(string $field): array
    {
        return [
            'before' => $this->before_snapshot[$field] ?? null,
            'after' => $this->after_snapshot[$field] ?? null,
        ];
    }
}